1. Field of the Invention
The present invention relates to a piezo-electric actuator drive circuit, and more particularly to a piezo-electric actuator drive circuit for driving a piezo-electric actuator wherein a drive voltage is applied to at least one of multiple polarizing sections, and to a piezo-electric actuator device furnished therewith.
2. Description of related art including information disclosed under 37 CFR §§1.97 and 1.98
In piezo-electric actuators such as standing wave ultrasonic motors (piezo motors), multiple polarizing sections are generally formed inside a unitary piezoelectric element, and a voltage pulse from a high-voltage power supply is applied to drive one or more of those polarizing sections. In actuators in which a voltage pulse is applied to one of multiple polarizing sections, the voltage pulse is applied to a different polarizing section in the case when the actuator is caused to rotate positively (positive direction drive) from the case in which the actor is cause to rotate negatively (reverse direction drive). In actuators in which a voltage pulse is applied to multiple polarizing sections, phases mutually differ between the voltage pulse waveforms applied to each polarizing section, and the various voltage pulse waveform phase relationships are changed between the case when the actuator is positively rotated (positive direction drive) and the case when the actuator is negatively rotated (reverse direction drive).
An oscillating actuator is described in Japanese Patent Publication 4406952 (Patent Citation 1). In this oscillating actuator, two alternating current signals are applied to an oscillator, and the slope of the shaft in the trajectory of the elliptical movement of the oscillator is controlled by varying at least one of the voltages of these alternating current signals or by varying the phase.